Synthesis of 'in situ' reinforced silicon nitride composites

摘要

The objective of this work was to investigate the effect of two different sintering additives (CeO_2 and Y_2O_3 + Al_2O_3), sintering time and amount of β-Si_3N_4 seeds on the densification, mechanical properties and microstructure of self-reinforced Si_3N_4 based composites obtained by pressureless sintering. Preparation of β-Si_3N_4 seeds, also obtained by a pressureless sintering procedure, is described Samples without seeds were prepared for comparison. The results imply that self-reinforced silicon nitride based composites with densities close to the theoretical values and with fracture toughness of 9.3 Mpa m~(1/2) can be obtained using a presureless sintering procedure.